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[Doc] Fix LangRef links referred in GetElementPtr.rst
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Authored by chenwj on May 5 2017, 5:05 PM.

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rengolin
• dberlin

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rG7533ac180c47: [Docs] Fix LangRef links referred in GetElementPtr.rst
rL303499: [Docs] Fix LangRef links referred in GetElementPtr.rst

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chenwj created this revision.May 5 2017, 5:05 PM

This is obvious, please feel free to commit things like this in the future without review.

This revision is now accepted and ready to land.May 20 2017, 8:41 AM

In D32929#760181, @dberlin wrote:

This is obvious, please feel free to commit things like this in the future without review.

@dberlin, I have not commit access, so would you help me to land it? :-)

Closed by commit rL303499: [Docs] Fix LangRef links referred in GetElementPtr.rst (authored by • gbiv). · Explain WhyMay 20 2017, 10:31 PM

This revision was automatically updated to reflect the committed changes.

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GetElementPtr.rst

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docs/GetElementPtr.rst

	=======================================			=======================================
	The Often Misunderstood GEP Instruction			The Often Misunderstood GEP Instruction
	=======================================			=======================================

	.. contents::			.. contents::
	:local:			:local:

	Introduction			Introduction
	============			============

	This document seeks to dispel the mystery and confusion surrounding LLVM's			This document seeks to dispel the mystery and confusion surrounding LLVM's
	`GetElementPtr <LangRef.html#i_getelementptr>`_ (GEP) instruction. Questions			`GetElementPtr <LangRef.html#getelementptr-instruction>`_ (GEP) instruction. Questions
	about the wily GEP instruction are probably the most frequently occurring			about the wily GEP instruction are probably the most frequently occurring
	questions once a developer gets down to coding with LLVM. Here we lay out the			questions once a developer gets down to coding with LLVM. Here we lay out the
	sources of confusion and show that the GEP instruction is really quite simple.			sources of confusion and show that the GEP instruction is really quite simple.

	Address Computation			Address Computation
	===================			===================

	When people are first confronted with the GEP instruction, they tend to relate			When people are first confronted with the GEP instruction, they tend to relate
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	Can I do type-based alias analysis on LLVM IR?			Can I do type-based alias analysis on LLVM IR?
	----------------------------------------------			----------------------------------------------

	You can't do type-based alias analysis using LLVM's built-in type system,			You can't do type-based alias analysis using LLVM's built-in type system,
	because LLVM has no restrictions on mixing types in addressing, loads or stores.			because LLVM has no restrictions on mixing types in addressing, loads or stores.

	LLVM's type-based alias analysis pass uses metadata to describe a different type			LLVM's type-based alias analysis pass uses metadata to describe a different type
	system (such as the C type system), and performs type-based aliasing on top of			system (such as the C type system), and performs type-based aliasing on top of
	that. Further details are in the `language reference <LangRef.html#tbaa>`_.			that. Further details are in the `language reference <LangRef.html#tbaa-metadata>`_.

	What happens if a GEP computation overflows?			What happens if a GEP computation overflows?
	--------------------------------------------			--------------------------------------------

	If the GEP lacks the ``inbounds`` keyword, the value is the result from			If the GEP lacks the ``inbounds`` keyword, the value is the result from
	evaluating the implied two's complement integer computation. However, since			evaluating the implied two's complement integer computation. However, since
	there's no guarantee of where an object will be allocated in the address space,			there's no guarantee of where an object will be allocated in the address space,
	such values have limited meaning.			such values have limited meaning.
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